Apparatus for slitting moving webs

ABSTRACT

Each one of the blades forming a web slitting blade pair and positioned at opposite sides of the web adjacent each other is provided with separate moving means. The separate moving means for a blade pair are connected to each other outside the web so that the blades may be moved together the web being between them and regardless whether the blades are in contact with each other in a cutting position or separated from each other in an inactive position. The blade moving means for the blades of a pair may comprise two threaded spindles extending along rail or the like on which blade supporting carriages are movable driven by said spindles. Further may a registering device be connected to the blade moving means to register the positions of all the blades and to transmit the information to a computer controlling the slitting operation.

['11] 3,786,705 [451 Jan. 22, 1974 APPARATUS FOR SLITTING MOVING WEBS[75] Inventor: 'Gerhard Walter Dorfel,

Weilheim-Teck, Germany [73] Assignee: A. Osakeyhtlo Ahlstrom,

Noormarkuu, Finland [22] Filed: Aug. 31, 1971 [21] Appl. No.: 176,542

[30] Foreign Application Priority Data 3,583,270 6/1971 Webb 83/428 X3,176,566 4/1965 Patterson, Jr.. 83/498 X 3,651,723 12/1969 Gallagher83/499 X Primary Examiner-J. M. Meister [5 7] ABSTRACT Each one of theblades forming a web slitting blade pair and positioned at oppositesides of the web adjacent each other is provided with separate movingmeans. The separate moving means for a blade pair are connected to eachother outside the web so that the blades may be moved together the webbeing between them and regardless whether the blades are in contact witheach other in a cutting position or separated-from each other in aninactive position. The blade moving means for the blades of a pair maycomprise two threaded spindles extending along rail or the like on whichblade supporting carriages are movable driven by said spindles. Furthermay a registering device be connected to the blade moving means toregister the positions of all the blades and to transmit the informationto a computer controlling the slitting operation.

4 Claims, 7 Drawing Figures mmmmez 1914 SHEET 1 0F 7 summaryPATENIEBmezmm I memos snmwr? APPARATUS FOR SLITTING MOVING WEBSBACKGROUND OF THE INVENTION 1. Field of the Invention Thisapplicationrefers to an apparatus for slitting moving webs, for examplepaper webs, or the like, into two or more webs of smaller width. Itspecifically relates to an apparatus of the type having blade pairs forcutting the web longitudinally into two or more narrower webs, whereinthe blade pairs are movable in the transversal direction of the webalong guide means, such as rails. I

2. Description of the Prior Art In machines such as this the slitting isusually achieved with the help of pair of rotating cutting blades, andthe width of the webs to be obtained can be varied by moving the bladesin the transversal direction of the webs. Since in the slitting machinesused so far it has been necessary to stop the machines for theadjustment of the blades, productional losses have incurred. Methodshave been invented for shortening the time needed for the adjustment ofthe blades, for example the method in which the transversal movement ofthe blades, which is obtained with the help of power mechanisms, isdetermined by special limiting devices, which can be adjusted while themachine is inoperation. The power mechanisms affect only one of theblades of the pair, and it is mentioned in the description that the paircan be coupled so that the blades move together, for example as has beenexplained in British Pat. No. 668,233. It is shown in the said patentspecification that the coupling of the blades for moving them is carriedout with the help of a pin in the holder of the upper blade; the pin ispressed into the hole in the socket of the lower blade. This means thatthe blades can be moved together only when the web is not moving betweenthem.

SUMMARY OF THE INVENTION According to this invention there is provided aweb slitting apparatus of the character described comprising separatemoving means for each one of the blades positioned adjacent each otheron opposite sides of the web and forming a blade pair, which movingmeans are connected to each other outside the web in such a way that theblades may be moved in pairs as desired with the web between themregardless whether the blades of the blade pair are in contact with eachother in a cutting position or separated from each other in an inactiveposition.

Thus, in a slitting apparatus. according to the invention each blade ofthe pair has its own moving device and the blades of a pair can be movedtogether the'web being between them. When the apparatus is in operation,the blades in the inactive position between two pairs of blades in thecutting position can be moved within the limits allowed by the blades inthe cutting position, but also the positions of the blades in theprocess of cutting can be adjusted.

The apparatus may also comprise a registering device connected to theblade moving means to register the positions of 'all the blades. Theslitting operation can thereby be controlled by a computer whichreceives information transmitted by the register device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I shows'a perspective view of aslitting apparatus according to the invention;

FIG. 2 is a longitudinal view of a portion of one embodiment of theapparatus, in cross section; FIG. 3 is another longitudinal view of thesame portion in cross section; FIG. 4 is a cross section of theembodiment of FIGS. 2 and 3.

FIG. 5 shows computer logic applicable for the control of the apparatus;

FIG. 6 shows another apparatus according to the invention, and

FIG. 7 shows a detail of the application according to FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, the referencenumeral 1 indicates the driving motor of ablade adjustment device, whichoperates threaded spindles 3 and 4 via gearing 2. When the threadedspindles 3 and 4 rotate, runners 5 and 6 move in the longitudinaldirection of the spindles. The blades with their hubs are attached tocarriages 7 and 8, which move along rails 9 and 10 respectively oneblade attached to a carriage 7 and one blade attached to a carriage 8 toform a pair. The driving motors of the blades have been left out of theillustration for the sake of clarity. Each blade pair may be positionedsuch that the blades are in contact in the cutting position or out ofcontact in the inactive position.

FIG. 2 shows an electromagnet ll housed in a blade carriage Whenprovided with current, the electromagnet 11 deforms a spring plate 12into such a shape that the runner 5 may pass by (as shown in thisfigure) and when it is without current, the underformed spring platetakes the shape shown in FIG. 3,in which case an extension of the runnerprojects into a hole in the spring plate and moves the carriage to whichthe plate is attached, along. FIG. 4 shows a cross section of thearrangement shown in FIGS. 2 and 3.

When the magnet is provided with current, there is a magnetic pullbetween blade carriage 7 and rail 9 so that the blade is immobilized.

The adjustment of the blades by computer takes place in the followingmanner; referring to FIG. 5.

The position of each blade is determined by the threaded spindleassociated with it. The rotational motion of the spindle is measured bya pulse sensor placed on the driving gear 13 and a pulse counter 14. Apredetermined number of pulses corresponds to a certain linear movementof the blade. The new adjustment values of the blades i.e., the bladenumber (each blade being identified by a number) and the new position,are fed I into the computer, which converts the new position register ofthe computer is zeroed and then the pulses received from the pulsesensors are accumulated to the register, or alternatively subtracted,depending on the rotational direction of the threaded spindles given bythe sensor 15. For practical reasons, the blades which have to be movedin one direction are shifted first, and then the blades to be moved inthe other direction are shifted. The blades may be moved while they arein the cutting or the waiting position.

FIG. 6 shows another application of the invention, in which the bladesare moved by endless belts 16, 17, which can be of an even surface orhave cogs to mate with the driving and turning gears 18, 19, and 21.

FIG. 7 shows a mechanism for use in a slide 7 or 8, with which mechanismthe blade carriage can be locked either to a moving belt or to astationary rail. The locking is produced by applying air pressure to oneside of piston 22 an extension thereof locking the belt between itselfand the carriage or locking the rail. Numeral 7 indicates the bladecarriage on a rail 9. The piston 22 has shafts 23 and 24 on each side,respectively. The piston is provided in a housing 7 in such way that apressure medium chamber 25 and 26 is formed on each side thereof. Theblade carriage 7 moves along the rail 9 guided by wheels 27 and 28 onboth sides of the flange of the rail. When pressure is provided in thechamber 26 below the piston, while the opposite chamber 25 is not underpressure, the piston shaft 23 is forced against the rail 9 therebylocking the blade carriage to the rail. When the pressure is brought toact in the chamber 25 at the upper side of the piston, while chamber 26is not under pressure, the piston shaft 24 forces the belt 16 againstthe carriage 7,locking the carriage to the belt for positioning of theblade. Between the end of the piston shaft and the belt is provided ametal plate 29 preventing the end of the shaft from penetrating thebelt.

I claim:

1. An apparatus for slitting moving webs of material and of the typehaving blade pairs for cutting the web longitudinally into at least twonarrower webs, which comprises blade pairs movable in the transversaldirection of the web along guide means, separate moving means for eachone of the blades positioned adjacent to each other on opposite sides ofthe web and forming a blade pair, said moving means comprising a pair ofseparate endless belts which are connected to each other outside theweb, the blades being movable in pairs with the web between them whenthe blades of the blade pair are in contact with each other in a cuttingposition and when the blades of the blade pair are separated from eachother in an inactive position, carrying means for moving the blades withsaid belts and a double-acting locking device for locking the carryingmeans to said belts and to said guide means.

2. An apparatus according to claim 1, further comprising a registeringdevice connected to the moving means for the blades to register thepositions of all the blades and to transmit the information for computercontrol of the slitting apparatus.

3. An apparatus according to claim 1, whrein the guide means are railsand said endless belts extend over the length of the rails and aredriven together by driving devices fitted outside the web.

4. An apparatus according to claim 3, wherein the double-acting lockingdevice for locking the belts to the carrying means comprises adouble-acting pressure medium driven piston which locks the carryingmeans to the belt for moving when it is pressed in one direction, andlocks the carrying means to the rail after the moving when it is pressedin the other direction.

1. An apparatus for slitting moving webs of material and of the typehaving blade pairs for cutting the web longitudinally into at least twonarrower webs, which comprises blade pairs movable in the transversaldirection of the web along guide means, separate moving means for eachone of the blades positioned adjacent to each other on opposite sides ofthe web and forming a blade pair, said moving means comprising a pair ofseparate endless belts which are connected to each other outside theweb, the blades being movable in pairs with the web between them whenthe blades of the blade pair are in contact with each other in a cuttingposition and when the blades of the blade pair are separated from eachother in an inactive position, carrying means for moving the blades withsaid belts and a double-acting locking device for locking the carryingmeans to said belts and to said guide means.
 2. An apparatus accordingto claim 1, further comprising a registering device connected to themoving means for the blades to register the positions of all the bladesand to transmit the information for computer control of the slittingapparatus.
 3. An apparatus according to claim 1, whrein the guide meansare rails and said endless belts extend over the length of the rails andare driven together by driving devices fitted outside the web.
 4. Anapparatus according to claim 3, wherein the double-acting locking devicefor locking the belts to the carrying means comprises a double-actingpressure medium driven piston which locks the carrying means to the beltfor moving when it is pressed in one direction, and locks the carryingmeans to the rail after the moving when it is pressed in the otherdirection.